这些河流和河川系统被称作“外源河流”，因为它们的源头位于干旱地区之外。

These rivers and river systems are known as "exogenous" because their sources lie outside the arid zone.

youdao

这些河流和河川系统被称作“外源河流”，因为它们的源头位于干旱地区之外。

These rivers and river systems are known as "exogenous" because their sources lie outside the arid zone.

youdao